With the development of computer technology and the increasing need for computer inter-networking, the packet switch data network based on IP or ATM is becoming ever strong. In contrast, the conventional PSTN voice network based on TDM doesn't have its service and control separated, so the providing of new services need a longer period, the conventional PSTN voice network seems incapable to meet the requirements of the increasing competitive market. In such condition, the next generation network system architecture with soft switch as its core control equipment emerges. In this architecture, the service and the call control as well as the call and carrying are absolutely separated.
As the core equipment of the next generation network system architecture, the soft switch control device is based on the packet switch data network, and performs functions of controlling call process, adapting access protocol, providing service interface, networking other networks (including PSTN, GSM, other soft switch control devices, etc.), and applying supporting system, etc., it employs standard protocol and open system architecture of application programming interface, which is convenient for a third party to participate in the employment and development, and makes the deployment of new services more quickly.
When a user U1 on a soft switch control device S1 calls a user U2 on another soft switch control device S2, S1 first has to be able to locate U2 on S2 so as to perform the service through S2, therefore, there must be a route relationship (U2, S2) on the S1. With the prevalence of the next generation network system architecture with soft switch as the core control equipment, there will be more and more soft switch control devices. If each soft switch control device is configured with the user route relationships on all of the other soft switch control devices, the route relationship data on each soft switch control device will certainly be huge and complex.
Furthermore, due to the inter-connection of network, the user on one soft switch control device can shake off the limitation of the conventional network to shift from one soft switch control device to another, while the soft switch control device still carries the original user character information. In order to connect with users on other soft switch control devices, the route relationship of other soft switch control devices must also be updated in time. Obviously, the complexity of networking makes the route relationship data of the soft switch control devices becomes difficult to maintain.